Mike,
sure, we will happily try to explain anything. If you are interested in a reply and you don’t understand it, just ask for a clarification.
In this case:
Normally (KDE3, Windows XP, whatever) you log in to your computer and you see a desktop. This is an analogy to your real office desktop, i.e., you have stuff on it: Tools (applications) and documents you work with. Some people have messy desktops, others have a tidy desktop.
KDE4 changed this approach: What you see isn’t the desktop, but a dashboard (think “car”, not “office” any longer). You aren’t supposed to have apps and documents on your dashboard, but small applets/widgets delivering information directly, without opening an app through an icon.
Common applets on a dashboard would be:
A clock
Post-it like notes
Some small applet showing disk usage
Another one showing CPU usage
An RSS feed
So, the dashboard is information, not storage.
Some of us have to do work with the computer, unfortunately. This means you have a Window sitting in front of the dashboard (like a browser, Oen Office Org writer, KMail) so you cannot see the information on the dashboard.
That’s what the “Show dashboard” widget is for: When you click it, it will bring all the dashboard widgets to the front and will dim your active applications.
The latest KDE4.2 Beta makes use of it and allows you to place widgets on the screensaver: That’s very cool. The screensaver starts and you see CPU temp, the clock, an RSS newsfeed, all stuff like that.
I hope this makes it clearer.
Uwe